Of course, even in US cities there's a lot of pride, attachment to, and involvement in "your neighbourhood" - which might just be a few blocks, or an entire city in it's own right, but you've still got pride for where you come from and a sort of "instant bond" with anyone that comes from the same place. I'm assuming that part isn't America-specific, honestly. Many places are absurdly proud of "townies" - people who grew up there, and still live there, and its expected that while you may (if you're successful) go out and explore the world for a few years, you eventually come back home to live with the "extended family" that is your neighbourhood again.
Note that your exact neighbours aren't necessarily part of the neighbourhood. There are many people who live in a town that are not part of the local community - but they are also treated as such, as outsiders, by the people who are, so there is that bit too. The closer an urban center there is nearby, the more "out-of-towner residents" you're likely to have - but that's part and parcel of the whole suburbanization thing, where they aren't coming to live in this town, they're coming to be in easy commuting distance of the city.
It's why there's so much kickback against "gentrification" in the US - it's the process where "neighbourhoods" are replaced by "strangers who live next to you", and it's something a lot of people here hate and for incredibly good (if ultimately selfish) reasons. You can't have a community with the sort of folks who are essentially just passing through until the next opportunity arises.
anyway, hah, this conversation should probably get it's own thread if we're going to continue it, esp. since it's drifted quite a bit.